An over-voltage protection system includes an electronic valve connected across two terminals of a circuit and an over-voltage detection circuit connected across one of the plurality of semiconductor devices for detecting an over-voltage across the circuit. The electronic valve includes a plurality of semiconductor devices connected in series. The over-voltage detection circuit includes a voltage divider circuit connected to a break-over diode in a way to provide a representative low voltage to the break-over diode and an optocoupler configured to receive a current from the break-over diode when the representative low voltage exceeds a threshold voltage of the break-over diode indicating an over-voltage condition. The representative low voltage provided to the break-over diode represents a voltage across the one semiconductor device. A plurality of self-powered gate drive circuits are connected to the plurality of semiconductor devices, wherein the plurality of self-powered gate drive circuits receive over-voltage triggering pulses from the optocoupler during the over-voltage condition and switch on the plurality of semiconductor devices to bypass the circuit.
Legal claims defining the scope of protection. Each claim is shown in both the original legal language and a plain English translation.
1. An over-voltage protection system comprising: an electronic valve connected across two terminals of a circuit, the electronic valve having a plurality of semiconductor devices connected in series; an over-voltage detection circuit connected across one of the plurality of semiconductor devices for detecting an over-voltage across the circuit, the over-voltage detection circuit comprising: a voltage divider circuit connected to a break-over diode in a way to provide a representative low voltage to the break-over diode, the representative low voltage representing a voltage across the one semiconductor device; an optocoupler configured to receive a current from the break-over diode when the representative low voltage exceeds a threshold voltage of the break-over diode indicating an over-voltage condition; and a plurality of self-powered gate drive circuits connected to the plurality of semiconductor devices, wherein the plurality of self-powered gate drive circuits receive over-voltage triggering pulses from the optocoupler during the over-voltage condition and switch on the plurality of semiconductor devices to bypass the circuit.
An over-voltage protection system safeguards circuits from excessive voltage. It uses an "electronic valve" (multiple semiconductor devices like thyristors or IGBTs in series) connected across the circuit's terminals to bypass current during an over-voltage. An over-voltage detection circuit monitors the voltage across one of these semiconductors. This detection circuit uses a voltage divider to feed a scaled-down voltage to a "break-over diode." When this reduced voltage exceeds the diode's threshold (indicating an over-voltage), the diode triggers an optocoupler. The optocoupler then sends triggering pulses to self-powered gate drive circuits. These gate drives then switch on all the semiconductors in the electronic valve, shunting the current away from the protected circuit.
2. The over-voltage protection system of claim 1 further comprising a mechanical switch to bypass the circuit for a long duration after the circuit has been bypassed by the plurality of semiconductor devices in the electronic valve.
The over-voltage protection system described above (with its electronic valve comprising series semiconductors, an over-voltage detection circuit including a break-over diode and optocoupler, and self-powered gate drives) includes an additional mechanical switch. This switch activates to provide a long-term bypass of the circuit *after* the electronic valve (semiconductors) have initially bypassed the circuit during the over-voltage event. This ensures continued protection even after the initial surge has subsided and potentially stresses the semiconductor devices.
3. The over-voltage protection system of claim 2 , wherein the electronic valve and the mechanical switch are open circuited during a non-fault condition.
In the over-voltage protection system described above (with an electronic valve of series semiconductors, an over-voltage detection circuit using a break-over diode and optocoupler, self-powered gate drives, *and* a mechanical bypass switch), both the electronic valve and the mechanical switch remain in an open-circuit state during normal operation, when no over-voltage condition exists. They only activate when an over-voltage is detected, leaving the protected circuit unaffected under normal circumstances.
4. The over-voltage protection system of claim 1 , wherein the semiconductor devices include thyristors, insulated gate bipolar transistors (IGBT) or controllable semiconductor devices.
In the over-voltage protection system described above (with its electronic valve comprising series semiconductors, an over-voltage detection circuit including a break-over diode and optocoupler, and self-powered gate drives), the semiconductor devices used in the electronic valve can be implemented as thyristors, insulated gate bipolar transistors (IGBTs), or other types of controllable semiconductor switching devices. The choice of device depends on factors like voltage and current handling requirements, switching speed, and cost.
5. The over-voltage protection system of claim 1 , wherein the break-over diode includes a low voltage break-over diode.
In the over-voltage protection system described above (with its electronic valve comprising series semiconductors, an over-voltage detection circuit including a break-over diode and optocoupler, and self-powered gate drives), the break-over diode within the over-voltage detection circuit is a low-voltage break-over diode. This means it triggers at a relatively low voltage, allowing for sensitive and rapid detection of over-voltage conditions across the monitored semiconductor device.
6. The over-voltage protection system of claim 1 , wherein the over-voltage detection circuit is connected across about a center switching device of the plurality of switching devices.
In the over-voltage protection system described above (with its electronic valve comprising series semiconductors, an over-voltage detection circuit including a break-over diode and optocoupler, and self-powered gate drives), the over-voltage detection circuit, which monitors the voltage and triggers the bypass, is connected across the *center* semiconductor device of the string of series-connected semiconductors in the electronic valve. This strategic placement may provide a more representative voltage reading for the overall valve.
7. The over-voltage protection system of claim 1 , wherein the break-over diode is connected in series with a low-pass filter to form a break-over diode branch, the low pass filter configured to block a displacement current of the break-over diode.
In the over-voltage protection system described above (with its electronic valve comprising series semiconductors, an over-voltage detection circuit including a break-over diode and optocoupler, and self-powered gate drives), a low-pass filter is connected in series with the break-over diode, forming a "break-over diode branch." The low-pass filter's purpose is to block displacement current from affecting the break-over diode's operation, preventing false triggering caused by transient noise or rapid voltage changes.
8. The over-voltage protection system of claim 7 further comprising a snubber circuit connected in parallel to the break-over diode branch to filter out high frequency noises.
The over-voltage protection system featuring an electronic valve, an over-voltage detection circuit with a break-over diode and optocoupler, self-powered gate drives, *and* a low-pass filter in series with the break-over diode, *also* includes a snubber circuit. This snubber circuit is connected in parallel with the break-over diode branch (the series combination of the break-over diode and the low-pass filter). The snubber circuit's function is to filter out high-frequency noise that might otherwise interfere with the break-over diode's accurate detection of an over-voltage.
9. The over-voltage protection system of claim 8 comprising a filtering network connected between the optocoupler and the break-over diode branch and configured to drive the optocoupler.
The over-voltage protection system featuring an electronic valve, an over-voltage detection circuit with a break-over diode and optocoupler, self-powered gate drives, a low-pass filter in series with the break-over diode, *and* a snubber circuit in parallel with the break-over diode branch, *also* includes a filtering network between the optocoupler and the break-over diode branch. This network is designed to properly drive the optocoupler, ensuring that the signal from the break-over diode is correctly transmitted to trigger the gate drives.
10. The over-voltage protection system of claim 1 , wherein the self-powered gate drive circuit of each of the semiconductor switches includes a power generation circuit which generates a voltage from a storage capacitor in parallel with a super capacitor.
In the over-voltage protection system described above (with its electronic valve comprising series semiconductors, an over-voltage detection circuit including a break-over diode and optocoupler, and self-powered gate drives), each self-powered gate drive circuit (one for each semiconductor device) includes a power generation circuit. This circuit generates the necessary voltage to switch the semiconductor using a storage capacitor in parallel with a supercapacitor. The supercapacitor provides a larger energy reservoir alongside the standard capacitor.
11. The over-voltage protection system of claim 10 , wherein the storage capacitor and the super capacitor are charged by a ballast resistor of the power generation circuit.
The over-voltage protection system featuring an electronic valve, an over-voltage detection circuit with a break-over diode and optocoupler, self-powered gate drives with power generation circuits featuring storage and super capacitors: *also* charges the storage capacitor and the super capacitor of each gate drive circuit using a ballast resistor in the power generation circuit. The ballast resistor limits the current flowing into the capacitors, preventing damage and ensuring a controlled charging process.
12. The over-voltage protection system of claim 11 , wherein the power generation circuit includes a voltage clamper to clamp the voltage across the storage capacitor.
The over-voltage protection system featuring an electronic valve, an over-voltage detection circuit with a break-over diode and optocoupler, self-powered gate drives with power generation circuits featuring storage and super capacitors charged via ballast resistor: *also* includes a voltage clamper within each power generation circuit to limit the voltage across the storage capacitor. This prevents overcharging and protects the capacitor from damage.
13. The over-voltage protection system of claim 11 , wherein the power generation circuit receives energy from the respective open-circuited semiconductor device during a non-fault condition.
The over-voltage protection system featuring an electronic valve, an over-voltage detection circuit with a break-over diode and optocoupler, self-powered gate drives with power generation circuits featuring storage and super capacitors charged via ballast resistor: *also* designs the power generation circuit in each gate drive to harvest energy from the associated open-circuited semiconductor device during normal (non-fault) operation. This allows the gate drive circuit to be self-powered, eliminating the need for external power supplies.
14. A method of bypassing a circuit during an over-voltage, the method comprising: connecting an electronic valve across two terminals of a circuit, the electronic valve formed by connecting a plurality of semiconductor devices in series; providing an over-voltage detection circuit across one of the plurality of semiconductor devices to detect an over-voltage across the circuit, wherein detecting the over-voltage includes: providing a representative low voltage representing a voltage across the one semiconductor device to a break-over diode by connecting a voltage divider circuit across the semiconductor device; receiving a current at an optocoupler from the break-over diode when the representative low voltage exceeds a threshold voltage of the break-over diode indicating an over-voltage condition; and utilizing the optocoupler for providing over-voltage triggering pulses to self-powered gate drive circuits of the plurality of semiconductor devices for turning on the plurality of semiconductor devices of the electronic valve to bypass the circuit during the over-voltage condition.
A method for protecting a circuit from over-voltage involves connecting an "electronic valve" (multiple semiconductor devices like thyristors or IGBTs in series) across the circuit's terminals. An over-voltage detection circuit monitors voltage across one of the semiconductors. Detecting over-voltage involves scaling down the monitored voltage with a voltage divider and applying it to a "break-over diode." When this scaled voltage exceeds the diode's threshold, the diode triggers an optocoupler, sending a current. The optocoupler sends trigger pulses to self-powered gate drive circuits connected to each semiconductor. These gate drives then switch on all the semiconductors in the electronic valve, shunting the current away from the protected circuit.
15. The method of claim 14 further comprising switching on a mechanical switch connected across the circuit to bypass the circuit for a long duration after initial bypass by the electronic valve.
The over-voltage protection method described above (using an electronic valve, over-voltage detection with a break-over diode and optocoupler, and self-powered gate drives to bypass the circuit) *also* involves activating a mechanical switch connected across the circuit. This switch turns on *after* the electronic valve initially bypasses the circuit, providing a long-duration bypass. This ensures continued protection even after the surge subsides, relieving stress on the semiconductor devices.
16. The method of claim 14 , wherein providing an over-voltage detection circuit includes connecting the over-voltage detection circuit across about a center switching device of the plurality of switching devices.
The over-voltage protection method described above (using an electronic valve, over-voltage detection with a break-over diode and optocoupler, and self-powered gate drives to bypass the circuit) detects the over-voltage by connecting the over-voltage detection circuit across the *center* switching device of the series of semiconductor switches.
17. The method of claim 15 further comprising connecting a low-pass filter in series with the break-over diode to form a break-over diode branch and to block a displacement current of the break-over diode.
The over-voltage protection method described above (using an electronic valve, over-voltage detection with a break-over diode and optocoupler, and self-powered gate drives to bypass the circuit, *and* including a mechanical bypass switch) *also* includes a low-pass filter connected in series with the break-over diode. This forms a "break-over diode branch," and the low-pass filter's job is to block displacement current from affecting the break-over diode's operation.
18. The method of claim 17 further comprising connecting a snubber circuit in parallel to the break-over diode branch to filter out high frequency noises.
The over-voltage protection method described above (using an electronic valve, over-voltage detection with a break-over diode and optocoupler, and self-powered gate drives to bypass the circuit, a mechanical bypass switch, and a low-pass filter in series with the break-over diode) *also* includes a snubber circuit connected in parallel with the break-over diode branch (series combination of the diode and low-pass filter). The snubber circuit filters out high-frequency noise from the break-over diode signal.
19. The method of claim 14 , wherein the self-powered gate drive circuit of each of the semiconductor switches includes a power generation circuit which generates a voltage from a storage capacitor in parallel with a super capacitor.
In the over-voltage protection method described above (using an electronic valve, over-voltage detection with a break-over diode and optocoupler, and self-powered gate drives to bypass the circuit, and a mechanical bypass switch), each self-powered gate drive circuit (one for each semiconductor switch) includes a power generation circuit. This circuit generates the voltage needed to switch the semiconductor using a storage capacitor in parallel with a supercapacitor, providing additional energy storage.
20. The method of claim 19 comprising charging the storage capacitor and the super capacitor by a ballast resistor of the power generation circuit.
The over-voltage protection method featuring an electronic valve, an over-voltage detection circuit with a break-over diode and optocoupler, self-powered gate drives with power generation circuits featuring storage and super capacitors *also* charges the storage capacitor and super capacitor within each gate drive's power generation circuit using a ballast resistor. The ballast resistor limits current and controls the charging process of the capacitors.
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November 5, 2014
May 2, 2017
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